Where to find passenger lists for early 1850's??

Where to find passenger lists for early 1850's??

Hi there,My gggrandfather William Galley was born in 1822 on the Isle of Wight.He married Charlotte Gower about 1849-1850.She was born 29 Sept 1831 in Hertfordshire.Their daughter Altie Louisa was born in 1851.

They came to Canada when Altie was a baby or about a year old.I assume they left from a port in England.Now,our Canadian passenger lists start in 1865.There are a few fragments before this date but I can't find these ancestors.Should I try various spellings of Galley? What would you suggest?Any help would be so appreciated.Thanks,Elaine